Melyngar was Gwydion's steed; Taran first saw her in the woods south of the Great Avren river, as Gwydion was tending the boy's wounds. She was captured by the Cauldron-Born under Achren's control and taken to Spiral Castle with Gwydion and Taran. After the Prince's disappearance, Melyngar helped Taran, Eilonwy, Fflewddur Fflam, and Gurgi flee the castle ruins. Melyngar's speed and endurance kept the Companions ahead of the pursuing Cauldron warriors. Later she found Medwyn's Valley, apparently through animal instinct, while she was carrying the injured Gurgi. Melyngar was sucked into The Black Lake with the group, and finally helped them reach Caer Dathyl.